LiFePO4Calc
Calibrated for Grade-A LiFePO4 85% DoD & MPPT Efficiency Standards

LiFePO4 Battery Bank & Solar System Size Calculator

Select your daily RV, vanlife, marine, or off-grid appliances below to calculate your exact Amp-Hour (Ah) battery capacity, solar panel wattage, MPPT controller, and AWG wire size.

1

Tap to Add Common Off-Grid Loads

Click any preset below to toggle it in your daily consumption list:

2

Your Daily Energy Breakdown

Total Daily Load: 0 Wh/day
3

Battery Voltage & Solar Conditions

Standard RV / Van
Usable Capacity

How many days your battery bank should last without solar recharging

1.5 Days
1 Day (Weekend Camper) 2 Days (Full-Time Boondocking) 4 Days (Remote Cabin)

U.S. & Europe Spring/Summer Average (4.5 hrs)

4.5 hrs/day
2.5h (Winter / PNW / UK) 4.5h (US Average) 6.5h+ (Arizona / Desert)

Your Custom System Blueprint

12V DC System
Recommended Battery
200Ah
Exact needed: 145Ah (2,560Wh)
Solar Panel Array
400W
2x 200W Panels (Full day charge)
MPPT Controller
40A
25% buffer incl.
Pure Sine Inverter
2000W
1200W peak
Battery Cable
2/0 AWG
200A ANL Fuse
Daily Energy Consumption: 1,450 Wh/day (1.45 kWh)
Matched Hardware Kit

Best-Value Components for Your Size

#1 Battery Match Grade-A Cells • 100A BMS

LiTime 12V 200Ah Plus LiFePO4 Lithium Battery

2,560Wh usable energy, 4000–15000 cycles, drop-in RV/Marine replacement.

Est. Street Price $469
Check Amazon Price LiTime Official (8% Off)
Solar + MPPT Match 99% MPPT Tracking

Renogy 400W 12V Monocrystalline Solar Kit + 40A Rover MPPT

Includes high-efficiency panels, Bluetooth MPPT controller, and tray cables.

Complete Kit $499
View Matched Solar & MPPT Kit on Amazon
Zero-Wiring Plug & Play Option

EcoFlow DELTA 2 Max (2,048Wh LiFePO4 Power Station)

Skip crimping wires: Built-in LiFePO4 battery, 2400W Pure Sine Inverter & 1000W MPPT in one box.

Compare All-in-One Solar Generator Deal
Reference Guide

LiFePO4 Battery Bank Sizing Chart (100Ah vs 200Ah vs 400Ah)

Not sure how Amp-Hours (Ah) translate to real-world camping or off-grid appliances? Here is what each standard 12.8V LiFePO4 bank size can comfortably power at an 85% usable Depth of Discharge.

Battery Bank (12.8V) Total Energy (Wh) Usable @ 85% DoD Min. Solar Needed Ideal Use Case & Appliances
100Ah 12V 1,280 Wh 1,088 Wh 200W Solar + 20A MPPT Weekend teardrops, trolling motors, CPAP machine + 12V fridge + LED lights.
200Ah 12V Most Popular 2,560 Wh 2,176 Wh 400W Solar + 40A MPPT Camper vans & Class B/C RVs: 12V Fridge, Starlink, laptops, diesel heater, roof fan.
300Ah 12V 3,840 Wh 3,264 Wh 600W Solar + 50A MPPT Full-time remote workers running Starlink 12h/day + induction cooktop / coffee maker.
400Ah 12V (or 200Ah 24V) 5,120 Wh 4,352 Wh 800W–1000W Solar Multi-day boondocking, microwave, air fryer, electric water heater, short A/C bursts.
600Ah+ (24V / 48V Recommended) 7,680+ Wh 6,528+ Wh 1,200W–2,000W Solar Off-grid cabins, tiny homes, and running 12V/24V mini-split air conditioners overnight.
Safety & ABYC Standards

Inverter Wire Gauge (AWG) & Fuse Sizing Reference

Undersized battery cables cause dangerous voltage drop, inverter low-voltage shutdowns, and fire hazards. Always size your pure copper cables for the maximum continuous amp draw of your inverter (under 6 feet round-trip distance).

Pro Tip: When to Switch from 12V to 24V/48V

If your inverter is larger than 2,500W, a 12V system pulls over 230 Amps—requiring expensive 4/0 AWG welding cable. Stepping up to a 24V or 48V LiFePO4 battery cuts amperage in half!

Inverter Size (12V) Max Draw (Amps) Copper Wire Gauge ANL / Class-T Fuse
1000W Inverter ~95 Amps 4 AWG Copper 125A – 150A Fuse
1500W Inverter ~140 Amps 2 AWG Copper 175A – 200A Fuse
2000W Inverter ~185 Amps 2/0 AWG Copper 250A Class-T Fuse
3000W Inverter ~280 Amps 4/0 AWG Copper 350A – 400A Class-T
Engineering Formulas & FAQ

Frequently Asked Questions About Sizing LiFePO4 & Solar

1. How many Ah LiFePO4 battery do I need for an RV or camper van?

For a standard weekend RV or camper van running a 12V compressor fridge (500–700Wh/day), LED lights, a MaxxAir roof fan, and charging laptops, a 200Ah 12V LiFePO4 battery (2,560Wh) is the industry sweet spot. If you run Starlink (500–600Wh/day), an induction cooktop, or a coffee maker daily, step up to a 300Ah or 400Ah bank.

2. How much solar panel wattage do I need for a 200Ah LiFePO4 battery?

A 12.8V 200Ah LiFePO4 battery holds 2,560 Watt-hours (Wh). Assuming an average of 4.5 peak sun hours per day and accounting for real-world solar panel heat/angle losses (~78% system efficiency), you should pair a 200Ah battery with 400W to 600W of solar panels and a 40A MPPT charge controller to replenish a full day's cycling.

3. Can you really discharge a LiFePO4 battery to 100% Depth of Discharge (DoD)?

Unlike Lead-Acid or AGM batteries (which suffer permanent sulfation damage if discharged below 50%), Lithium Iron Phosphate (LiFePO4) batteries can safely discharge to 100%. However, designing your off-grid bank around an 85% Depth of Discharge prevents unexpected BMS low-voltage cutoffs during high inverter surges and extends cell lifespan past 6,000 cycles (15+ years).

4. What is the exact formula used by this calculator?

Required Ah = (Daily Total Wh × Days of Autonomy) ÷ (System Voltage × DoD % × 0.92 Inverter Efficiency)
Required Solar (W) = Daily Total Wh ÷ (Peak Sun Hours × 0.78 Solar System Efficiency)
Required MPPT (A) = (Solar Array Watts ÷ System Voltage) × 1.25 NEC Safety Factor

System blueprint copied to clipboard!